Links

Classifications

H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes

H04W52/02—Power saving arrangements

H04W52/0209—Power saving arrangements in terminal devices

H04W52/0212—Power saving arrangements in terminal devices managed by the network, e.g. network or access point is master and terminal is slave

H04W52/0216—Power saving arrangements in terminal devices managed by the network, e.g. network or access point is master and terminal is slave using a pre-established activity schedule, e.g. traffic indication frame

H04W68/00—Notification of users, e.g. alerting for incoming communication or change of service

H04W68/005—Transmission of information for alerting of incoming communication

Y02D70/00—

Abstract

A method of updating channel information by a mobile station (MS) that is in power saving mode is disclosed. More specifically, the method includes the MS which receives status information of a first channel descriptor and transmission frame information which includes when the first channel descriptor is to be transmitted. Furthermore, the MS compares status information of the first channel descriptor with status information of a second channel descriptor. Here, the second channel descriptor is stored in the MS. Lastly, if the compared status information are different, the MS receives the first channel descriptor according to the transmission frame information.

Description

i

A METHOD OF UPDATING CHANNEL INFORMATION BY A MOBILE

STATION THAT IS IN POWER SAVING MODE

Technical Field

The present invention relates to a method of updating channel information, and

more particularly, to a method of updating channel information by a mobile station that

is in power saving mode.

Background Art

In a Broadband Wireless Access System, an operation of a power saving mode

is as follows. A paging zone refers to all the paging areas covered by a plurality of base

stations. Here, all the base stations in the same paging zone share a same paging cycle

(i.e., Paging_Cycle) and a same paging offset (i.e., Paging_Offset).

In the system, a mobile station (MS) can request to enter a power saving mode

from the base station (BS). The BS can then permit the MS to enter the power saving

mode by transmitting its paging group identification (i.e, Paging_Group_ID) and the

paging cycle and the paging offset, both corresponding to the paging group ID. Upon

receiving the paging group ID, the corresponding paging cycle, and the corresponding

paging offset, the MS can then enter the power saving mode.

During the power saving mode, the MS receives a broadcast message in a form

of a paging broadcast message (i.e., MOB-PAG-ADV) from the BS at specified paging

cycle. From the paging broadcast message, the MS can determine whether to maintain

or terminate the power saving mode.
If a situation arises where the MS has to send uplink traffic to the BS, the MS

can terminate the power saving mode anytime. Conversely, if a situation arises where

the MS, which is in the power saving mode, has to receive downlink traffic from the

BS, the BS sends the paging broadcast message to instruct the MS to terminate the

power saving mode.

Alternatively, if the MS, which is in a power saving mode fails to receive the

paging broadcast message at the specified time as a result of moving to another paging

zone or by failure to synchronize, then the MS has to terminate the power saving mode.

Disclosure of the Invention

Accordingly, the present invention is directed to a method of updating channel

information by a mobile station that is in power saving mode that substantially

obviates one or more problems due to limitations and disadvantages of the related art.

An object of the present invention is to provide a method of updating channel

information by a mobile station that is in power saving mode.

Another object of the present invention is to provide a method of providing

channel information by a base station to a mobile station that is in power saving mode.

A further object of the present invention is to provide an apparatus for updating

channel information by a mobile station that is in power saving mode.

Additional advantages, objects, and features of the invention will be set forth in

part in the description which follows and in part will become apparent to those having

ordinary skill in the art upon examination of the following or may be learned from

practice of the invention. The objectives and other advantages of the invention may be
realized and attained by the structure particularly pointed out in the written description

and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with the

purpose of the invention, as embodied and broadly described herein, a method of

updating channel information by a mobile station (MS) that is in power saving mode

includes the MS which receives status information of a first channel descriptor and a

transmission frame information which includes when the first channel descriptor is to

be transmitted. Furthermore, the MS compares status information of the first channel

descriptor with status information of a second channel descriptor. Here, the second

channel descriptor is stored in the MS. Lastly, if the compared status information are

different, the MS receives the first channel descriptor according to the transmission

frame information.

In another aspect of the present invention, a method of providing channel

information by a base station (BS) to a mobile station (MS) that is in power saving

mode, includes the BS which transmits status information of a first channel descriptor

and transmission frame information which includes when the first channel descriptor is

to be transmitted. Moreover, the BS transmits the first channel descriptor according to

the transmission frame information.

Yet, in another aspect of the present invention, an apparatus for updating

channel information where the apparatus is in power saving mode. The apparatus

includes a receiver for receiving status information of a first channel descriptor and a

transmission frame information which includes when the first channel descriptor is to

be transmitted, hi addition, the apparatus includes a comparator for comparing status
information of the first channel descriptor with status information of a second channel

descriptor. Here, the second channel descriptor is stored in a memory of the MS. Lastly,

the receiver is used to receive the first channel descriptor according to the transmission

frame information, if the compared status information from the comparator are

different.

Another aspect of the present invention includes a method of updating channel

information by a mobile station (MS) that is in power saving mode. In the method, the

MS receives status information of a channel descriptor and a transmission frame

information which includes when the channel descriptor is to be transmitted.

Furthermore, the MS recognizes a change in the status information of the channel

descriptor since a last decoded status information. Lastly, the MS receives the channel

descriptor according to the transmission frame information.

In another aspect of the present invention, a method of updating channel

information by a mobile station (MS) that is in power saving mode includes the MS

which receives a transmission frame information which includes a specified frame at

which a channel descriptor is to be transmitted. Moreover, the MS recognizes the

specified frame for receiving the channel descriptor which contains information

different from channel descriptor information stored in the MS. Lastly, the MS

receives the channel descriptor at the specified frame.

It is to be understood that both the foregoing general description and the

following detailed description of the present invention are exemplary and explanatory

and are intended to provide further explanation of the invention as claimed.
Brief Description of the Drawings

The accompanying drawings, which are included to provide a further

understanding of the invention and are incorporated in and constitute a part of this

application, illustrate embodiment(s) of the invention and together with the description

serve to explain the principle of the invention. In the drawings;

FIG. 1 is a diagram illustrating an example of an operation of a power saving

mode according to updated status information of a DCD/UCD;

FIG. 2 illustrates an example of a transmission operation of a paging broadcast

message or a common downlink notification DL-MAP IE;

FIG. 3 is a diagram illustrating an example of an operation of a DCD/UCD

transmission offset;

FIG. 4 illustrates is a diagram illustrating an example of a paging cycle

synchronized to a DCD/UCD transmission cycle;

FIG. 5 is a diagram illustrating an example of an initial ranging operation by

the MS according to coding scheme and modulation schemes changes in the BS; and

FIG. 6 is diagram illustrating an example of an operation using a frame number

instead of a DCD/UCD transmission offset.

FIG. 7 is a diagram illustrating an example of an apparatus in a power saving

mode which updates channel information.

Best Mode for Carrying Out the Invention

Reference will now be made in detail to the preferred embodiments of the

present invention, examples of which are illustrated in the accompanying drawings.
Wherever possible, the same reference numbers will be used throughout the drawings

to refer to the same or like parts.

In connection with the present invention, a more detailed description of a

power saving mode as well as a Downlink Channel Descriptor (DCD) and an Uplink